Heating shuttering panels

ABSTRACT

The specification describes a method of heating hollow shuttering panels for use in casting concrete and similar hardenable materials in which method hot air is used and is arranged to flow through the panel directly in contact with the internal surface of one or more of the sides of the panel. In a rectangular panel described by way of example the interior of the panel is divided, by partitions extending between the sides of the panel, to provide two manifolds extending along opposite edges of the panel and ducts extending between and communicating at their ends with the two manifolds. Hot air from a heating means is passed into one of the manifolds, through the ducts to the other manifold and thence back to the heating means for reheating and recirculation.

United States Patent 1 Kleiber HEATING SHUTTERING PANELS [76] Inventor:Armin Kleiber, Mozarstr. 5,

Karlsruhe, Germany [22] Filed: Oct. 18, 1972 [21] Appl. N0.: 298,590

[30] Foreign Application Priority Data Dec. 13, 1971 Germany P 21 61707.2

[52] US. Cl 432/223, 165/86, 432/9 [51] Int. Cl F28f 5/00 [58] Field ofSearch 165/81; 432/178, 223, 9

5/1972 MitchelletaL. l/1919 Brand [451 Feb. 19, 1974 PrimaryExaminer-John J. Camby Attorney, Agent, or Firm-Wenderoth, Lind & Ponack[57] ABSTRACT The specification describes a method of heating hollowshuttering panels for use in casting concrete and similar hardenablematerials in which method hot air is used and is arranged to flowthrough the panel directly in contact with the internal surface of oneor more of the sides of the panel. In a rectangular panel described byway of example the interior of the panel is divided, by partitionsextending between the sides of the panel, to provide two manifoldsextending along opposite edges of the panel and ducts extending betweenand communicating at their ends with the two manifolds. Hot air from aheating means is passed into one of the manifolds, through the ducts tothe other manifold and thence back to the heating means for reheatingand recirculation.

4 Claims, 3 Drawing Figures PAIENIEDHEB 1 91914 amazon 4 HEATINGSHUTTERING PANELS BACKGROUND OF THE INVENTION The invention relates to amethod of heating shuttering panels having cavities into which a heatingmedium is introduced, and to heated shuttering apparatus.

In the production of planar structural elements from concrete or otherhardenable materials that are charged into forming means in a castingprocess, use is made of shuttering panels which may be designed to beheated in order to accelerate the setting process. Shuttering panels ofthis kind are used singly, forexample in the horizontal position ontilting tables, or are used in the vertical position when made up into aset, which can either be stationary or transportable. The known heatingsystems comprise pipe arrangements which are inserted in the shutteringpanels and secured by various means. These pipe systems carry steam orhot oil, and high-pressure flexible connections have to be providedbetween the heating means and the shuttering panels. A system of thiskind, employing pipe arrangements is very expensive and carries seriousdisadvantages as regards the production of the shuttering panels and thecarrying out of repairs. Since the pipes are caused to oscillate by thevibrators connected to the shuttering panels, breakage of the pipesoccurs relatively frequently, so that such arrangements have only ashort service life. A further disadvantage of the known pipe systemsresides in the fact that heat is dissipated mainly at the surfaces ofthe pipes, so that the sheeting of the shuttering panels has to performthe function of distributing the heat across the area of the panels.This results in uneven distribution of heat and can, for example, leadto charring of the concrete in zones near the pipes if supervision isnot carried out properly and heat is allowed to build up.

SUMMARY OF THE INVENTION The object of the invention is to provide amethod of heating shuttering panels which avoids the use of pipe systemslikely to cause trouble and which results in substantially uniformheating of the surface of the shuttering. Accordingly the inventionprovides, in one aspect a method of heating a hollow shuttering panelcomprising passing hot air, constituting the heating medium, from aheating means directly over the internal surface of at least one side ofthe panel. The hollow interior of the shuttering panels may be open orsubdivided, and the inflowing hot air heats the entire forming face orfaces of the shuttering panel in a substantially uniform manner, and thelikelihood of cracks developing as a result of the movements imparted bythe vibrator is greatly reduced. The pressure of the hot air used isconveniently just below or slightly above normal pressure and less than3 atmos., so that high-pressure connections between the heating meansand the shuttering panel are not required. The heating means can simplytake the form of an air heater with a fan unit, and heat losses arereduced by re-circulation of the heating medium.

In another aspect the invention provides shuttering apparatus comprisinga hollow shuttering panel comprising at least one side which has anexternal surface providing a moulding surface and which has an internalsurface and having an inlet union and an outlet union, the panelproviding within it a fluid flow path extending from the inlet union tothe outlet union, at least part of which path is defined by the internalsurface of the one side, and air heating means connected to supply hotair to the flow path through the inlet union and to receive the air backagain from the outlet union for reheating.

In one preferred arrangement, the inlet union and the outlet union arefitted at opposite ends of one edge of the shuttering panel, and theheating means can be disposed adjacent such edge of the panel. Anarrangement of this kind offers advantages in the overall installationof production plants, particularly when use is made of shuttering panelsthat are transportable along a production line.

It is also advantageous where a plurality of panels are put together toform a shuttering set, to provide all the shuttering panels with inletand outlet unions for connection to respective complementary inlet andoutlet unions on the heating means, the heating means being located atone end of the panels so that all the shuttering panels can be connectedsimultaneously to the heating means.

The shuttering panels can be arranged for movement relative to thestationary heating means over the floor, e.g., on rails or with the aidof bogeys fitted with rollers or spherical runners. This arrangement ispreferred for production lines in which the individual shuttering panelsare first made up into a set, using panels that have come from apretreatment line, and then passed as a set from the casting station toa heating station in which the heating means is connected to theshuttering panels. For other applications it may be advantageous for theheating device to be displaceable relative to shuttering panels whichare stationary, at least at the heating station, so that the individualshuttering panels or sets of shuttering panels can be successivelyconnected to the heating means. In this way, considerable savings in thecost of the heating means can be achieved.

For the purpose of improving the distribution of flow of the hot airwith a view to achieving uniform heating of the shuttering surface, itmay also be advantageous to provide guide elements in the interior ofthe shuttering panel for directing the current of heating medium in therequired manner. Such guide elements can take various forms; for examplethey may be guide strips, perforated metal sheets, wire mesh and thelike. In one advantageous arrangement, there are provided, as guideelements or in addition to the guide elements already present,partitions containing openings of differing cross-sections such that theopenings adjacent the inlet and outlet unions are of smallercross-section than those more remote from the unions. In this way, thepressure-drop occurring during the movement of the hot air can be takeninto account for the purpose of producing a uniform heating effect. Itmay also be advantageous to provide, in addition to the partitions,walls which divide up the interior of the shuttering panel. This furtherincreases the evenness of the heating.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 3 shows a shuttering panel, withparts thereof cut away, for use in an apparatus as shown in FIGS. 1 and2.

DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 and 2 illustrate atransportable set of shuttering panels 1, which can be moved on bogeys 2and 3 travelling on rails 4 and 5 in a production line.

Each of the shuttering panels 1 has an inlet union 6 and an outlet union7 on the same end edge for supplying and returning the heating medium.The inlet and outlet unions 6 and 7 of each shuttering panel 1 areconnected by resilient intermediate members in the form of flexiblemetal pipes 8 and 9, to the complementary unions l0 and 11 ofa heatingmeans 12. This heat-' ing means 12 consists of an electrical, gas-firedor oilfired heat-producing unit of which the hot air can be caused tocirculate over a closed path through the hollow interior of theshuttering panels 1. The unions 10 and 11 on the heating means 12 aredisposed in parallel with each other between suitable ports or manifoldsl3 and 14.

The travel of the air inside a hollow shuttering panel is illustrateddiagrammatically in FIG. 1 by means of flow-lines. The air is caused toflow in the direction of these lines with the aid of guide elements, theform of which will be explained by reference to FIG. 3.

FIG. 3 shows a shuttering panel 1, parts of which are cut away to showthe construction, having fitted internally thereof two partitions l7 and18 forming passages 15 and 16 for the hot air. The lower hot-air passage15 communicates with the inlet union 6, and the upper hot-air passage 16communicates with the outlet union 7 of the shuttering panel 1. Each ofthe partitions 17 and 18 contains a row of openings 19 and 20respectively, the cross-sectional areas of which increase withincreasing distance from the inlet and outlet unions 6 and 7respectively. In this way, the pressure-drop in the hot-air passage 15and 16 can be taken into account for the purpose of achieving uniformdistribution of the heating medium. The interior of the shuttering panelis divided into a plurality of ducts by means of vertical separatingwalls 21 located between the partitions l7 and 18. An opening 19, 20 ineach of the partitions is provided opposite the ducts so that themanifolds l5, 16 formed by the partitions communicate with each othervia the vertical ducts.

The shuttering panels 1 are produced as box-like hollow bodies andpreferably are made of metallic materials having good thermalconductivity. To prevent heatlosses, appropriate lagging can be providedat the edges of the sides of the shuttering panels 1 and/or on the pipesconnecting the panels to the heating means.

It may also be advantageous not to form the two hotair manifolds 15 and16 by means of partitions l7 and 18 as illustrated, but to use lengthsof tubing of rectangular cross-section. These would then also eachcontain a row of openings 19 and 20. Instead of a single openingproviding access to each associated duct in the shuttering panel, aplurality of openings could be provided, in which case the totalcross-sectional area of the openings associated with each chamber mustincrease from one set of openings to the next in a direction away fromthe inlet and outlet unions.

I claim:

1. In an apparatus for manufacturing planar structural elements fromconcrete or other hardenable materials with hollow shuttering boardswhich are singly movable in a production line and which may be connectedtogether to build up a multicompartment mold the improvement wherein:

said shuttering boards each comprising a closed body having a heatingspace and having an inlet union and an outlet union at the same sideedge of said shuttering board in connection with said heating space; and

a heating air generator having connections, said inlet and outlet unionsbeing fittable with said connections of said heating air generator tobuild up a closed heating air circuit for each of the hollow shutteringboards.

2. Apparatus according to claim 1, in which said heating air generatoris movable with respect to said shuttering boards.

3. Apparatus according to claim 1, further comprising guiding elementspositioned in said heating space of each of said hollow shutteringboards.

4. Apparatus according to claim 3, wherein each of said guiding elementscomprises distributing channels positioned at opposite sides within eachof said hollow shuttering boards, and a plurality of parallel ductsextending from one distributing channel to the other, said distributingchannels being in connection with said inlet and outlet unions andhaving apertures each communicating with the parts of said heating spaceformed by said parallel ducts, the area of said apertures in each ofsaid channels progressively increasing from duct to duct in a directionaway from said inlet and outlet unions.

1. In an apparatus for manufacturing planar structural elements fromconcrete or other hardenable materials with hollow shuttering boardswhich are singly movable in a production line and which may be connectedtogether to build up a multicompartment mold the improvement wherein:said shuttering boards each comprising a closed body having a heatingspace and having an inlet union and an outlet union at the same sideedge of said shuttering board in connection with said heating space; anda heating air generator having connections, said inlet and outlet unionsbeing fittable with said connections of said heating air generator tobuild up a closed heating air circuit for each of the hollow shutteringboards.
 2. Apparatus according to claim 1, in which said heating airgenerator is movable with respect to said shuttering boards. 3.Apparatus according to claim 1, further comprising guiding elementspositioned in said heating space of each of said hollow shutteringboards.
 4. Apparatus according to claim 3, wherein each of said guidingelements comprises distributing channels positioned at opposite sideswithin each of said hollow shuttering boards, and a plurality ofparallel ducts extending from one distributing channel to the other,said distributing channels being in connection with said inlet andoutlet unions and having apertures each communicating with the parts ofsaid heating space formed by said parallel ducts, the area of saidapertures in each of said channels progressively increasing from duct toduct in a direction away from said inlet and outlet unions.